I'm really loving this throwback to vintage styles lately.  Last season it was floral prints (still great, especially in pretty scarves), and my new favorite trend is Full Miniskirts.  More fashion than clubbing (although you could certainly wear this look out to the bar), a full mini is perfect to add padding to a small behind or just a trendy twist to your style.  As noted by Fab Sugar, minis can be worn with bare legs, with leggings (please, don't), or with dark tights (please, do) for fall.

The full mini-skirt is a Fall Must-Have and works seamlessly with other current trends, particularly dark and textured tights and Fall Peep Toe Pumps.  Minis are available from micros to longer styles that reach down to the knee, so pick the skirt you are comfortable in.

Animal print mini from Forever 21

I would love the skirt above with a pair of brightly colored tights and black ankle boots.  Top with a slim cardigan for chilly September mornings.

A more pleated skirt is OK, but look for soft fabric with loose folds as opposed to sharp creases.  Plaid is trendy as well, so it's the perfect time to live out any schoolgirl fantasies.

From Urban Outfitters, I love the Kimchi Skirt on the right because it's named for my favorite food.  When wearing a print on your skirt, stick to bare legs or a dark tight in a solid shade.  I'm of course partial to heels, but comfy flats over warm tights are perfect for running from class to class.

These two blue minis are from TopShop

TopShop has a great selection of mini skirts perfect for this trend, including pleats, pockets, and other poofy styles.  Urban Outfitters & Forever 21 also have good selections.  As always, thrift shopping is another solution.